“Two things fill the mind with ever new and increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above and the moral law within.”
Immanuel Kant, Critique of Practical Reason, 1788
The cosmos, vast and awe-inspiring, has always captivated humanity. Modern telescopes like the NASA Webb, showcasing images of galaxies billions of years old from the depths of space, amplify this wonder. As NASA notes, “Webb’s image is approximately the size of a grain of sand held at arm’s length, a tiny sliver of the vast universe,” yet within this minuscule view, thousands of galaxies emerge.
The sheer scale of the universe is almost incomprehensible. Today, we understand that our own galaxy, the Milky Way, is just one among potentially trillions of galaxies scattered across the cosmos. But this understanding is relatively recent. Remarkably, over two centuries ago, Immanuel Kant (1724–1804), the renowned German philosopher of the Enlightenment, theorized about a universe filled with multiple galaxies and a concept of “deep time” in his 1755 work, Universal Natural History and Theory of the Heavens.
Kant’s Revolutionary Idea: The Universe of Island Universes
Published anonymously, Kant’s Natural History and Theory of the Heavens was an ambitious attempt to revolutionize astronomy. At a time when astronomical progress seemed stagnant since Huygens, Kant aimed to unify existing observations with groundbreaking hypotheses. He proposed that the “fixed stars,” believed to be stationary, were in fact suns, moving and organized into vast systems, much like our solar system but on an immense scale.
“According to this representation, the system of the fixed stars may be described approximately by the planetary one, if the latter is extended infinitely. Because if, instead of the six planets with their ten satellites, we assume as many thousands of them and instead of the twenty-eight or thirty comets that have been observed, we assume a hundred or thousand times as many. If we think of these very bodies as self-illuminating, then … they would create the appearance as of the fixed stars of the Milky Way.”
Kant 1755 – Natural History and Theory of the Heavens
Kant’s innovation was to suggest that the Milky Way itself was not the entirety of the universe, but rather one “system of fixed stars” among many. He argued that these “fixed stars” weren’t fixed at all, but moving suns, appearing stationary only due to their immense distance. He envisioned the Milky Way as a flattened, disc-like system, a concept surprisingly close to our modern understanding of spiral galaxies.
Expanding on this, Kant introduced the concept of “island universes.” He theorized that if the Milky Way, a system of countless stars, were viewed from an unimaginable distance, it would appear as a faint, elliptical patch of light. He then boldly proposed that the faint nebulae observed through telescopes at the time might not be clouds of gas within our galaxy, but rather other “Milky Ways” – independent galaxies located at vast distances.
I now come to that part of the doctrine advanced that makes it most attractive because of the sublime view it presents of the plan of creation. The sequence of thoughts that have led me to it is short and plain. It consists of the following. If a system of fixed stars, in which their positions are in a common plane, such as we have sketched the Milky Way, is so far away from us that all recognition of the individual stars of which it consists cannot be detected even by a telescope; if its distance relative to the distance of the stars of the Milky Way is the same as the distance of the Sun to us – in short, if such a world of fixed stars is viewed at such an immeasurable distance from the eye of the observer which is outside it, then it will appear under a small angle as a minute space illuminated by a weak light, the shape of which will be round as a circle when its plane presents itself straight to the eye and elliptical when it is seen from the side.
Kant 1755 – Natural History and Theory of the Heavens
Centuries Ahead: Kant and the Great Debate
Kant’s idea was remarkably prescient. In the 1920s, the astronomical community engaged in the “Great Debate” about the nature of these spiral nebulae. Were they, as Kant proposed, independent galaxies (“island universes”) far beyond our Milky Way, or were they simply gas clouds within our own galaxy?
While telescopes of Kant’s time couldn’t definitively prove his theory, his philosophical intuition was astonishingly accurate. He argued that the observed nebulae were “systems of many stars, whose distance from us exhibits them as being in so narrow a space that the light… becomes a uniform pale shimmering with their immeasurable number.” He even speculated about hierarchical structures, anticipating galaxy clusters, envisioning “higher orders of worlds” interconnected in ever larger systems.
It took more powerful telescopes and advanced astronomical techniques in the 20th century to finally resolve the Great Debate and confirm Kant’s vision. Edwin Hubble’s observations in the 1920s provided conclusive evidence that spiral nebulae were indeed galaxies, vast star systems located far beyond the Milky Way, vindicating Kant’s groundbreaking theory.
The Cosmic Sublime and Humanity’s Place
Kant’s contemplation of the vast universe led him to philosophical reflections on humanity’s place within it. He grappled with the feeling of insignificance in the face of cosmic immensity, echoing Blaise Pascal’s famous fear of “the eternal silence of these infinite spaces.” However, unlike Pascal, Kant found not terror, but a sense of the “cosmic sublime” in this realization.
“If the magnitude of a planetary system in which the Earth is as a grain of sand and scarcely noticeable puts our reason into a state of wonderment, then with what amazement are we delighted when we contemplate the infinite multitude of worlds and systems that constitute the sum total of the Milky Way; but how much does this amazement increase when one becomes aware that all these immeasurable orders of stars in turn are the unit of a number whose end we do not know.”
Kant 1755 – Natural History and Theory of the Heavens
For Kant, the sheer scale of the universe, far from diminishing humanity, elevated our reason and spirit. The ability to comprehend such vastness, to grasp the concept of countless galaxies extending into infinity, was a testament to the power of human intellect. This sense of awe and wonder at the cosmos connected deeply with his ethical philosophy.
Deep Time and Cosmic Evolution
Kant’s cosmological vision also encompassed the concept of “deep time” and a dynamic, evolving universe. He imagined the cosmos as a realm of constant creation and transformation, stretching back into an unfathomable past and extending into an infinite future.
…the infinite space of the divine presence, where the store of all possible formations of nature can be found, lies buried in a silent night full of matter to serve as the material for worlds to be generated in the future, and of the driving force to set them…in motion, that…will begin those motions with which the infinitude of those empty spaces is to be brought to life in the future. Perhaps a number of millions of years has passed before the sphere of formed nature in which we find ourselves has grown to [current] perfection.
Kant 1755 – Natural History and Theory of the Heavens
He proposed a nebular hypothesis for the formation of stars and planetary systems from swirling clouds of gas and dust, a remarkably modern idea that predated later scientific formulations. Kant envisioned a universe in constant flux, with “millions and whole mountain ranges of millions of centuries” passing as new worlds and systems formed and decayed. This dynamic view of cosmic evolution was centuries ahead of its time.
Speculations on Alien Life (and a Product of His Time)
Intriguingly, Kant also speculated about extraterrestrial life. He believed that the plenitude of nature suggested the existence of inhabitants on other planets, even venturing into now-outdated and problematic ideas about a hierarchy of intelligence linked to planetary distance from the Sun. While these aspects of his thought reflect the prejudices of his era, his general consideration of alien life forms is noteworthy for its time. He even pondered the adaptations of life to different planetary environments, considering factors like temperature and day length, showing a proto-ecological awareness.
Kant’s Enduring Legacy: From Starry Skies to Moral Law
Kant concluded his Natural History with a reflection on the profound experience of contemplating the starry sky, an experience that evokes a sense of “bliss and sublimity.” This sentiment resonates deeply with the famous quote from his Critique of Practical Reason, linking the awe of the “starry heavens above” with the “moral law within.”
“Two things fill the mind with ever new and increasing admiration and reverence, the more frequently and persistently one’s meditation deals with them: the starry sky above me and the moral law within me.”
Kant 1788 Critique of Practical Reason
For Kant, the vastness of the cosmos, far from diminishing human value, served to highlight the unique capacity of human reason and morality within this grand universe. His early cosmological insights, particularly his theory of galaxies, stand as a testament to his intellectual genius and his profound ability to anticipate scientific discoveries centuries before their time. Looking up at the night sky, or gazing at the breathtaking images from modern telescopes, we can still feel the “bliss and sublimity” that Immanuel Kant experienced and so eloquently articulated, connecting us to a cosmic vision he pioneered.
References
- Kant, Immanuel. Universal Natural History and Theory of the Heavens. Translated and edited by Stanley L. Jaki. Scottish Academic Press, 1981.
- Kant, Immanuel. Critique of Practical Reason. Translated by Mary Gregor. Cambridge University Press, 1997.
- The Great Debate (1920) – Wikipedia
- NASA Webb Telescope Images. https://www.nasa.gov/webbfirstimages
